The primary subject of the invention is a profile gauge that embodies a measurement geometry for a tool that has a toothed profile designed for the skiving of toothed work pieces, wherein the profile gauge serves to determine at least one measurement quantity which can be used for a skiving process that is to be performed with the tool and wherein, in a phase of said process, the toothed profile to be generated on the work piece is formed by a meshing engagement with the teeth of the tool. The invention further encompasses a measuring device equipped with the profile gauge as well as a measurement method that is based on the profile gauge. More generally, the invention for which protection is sought concerns profile gauges for tools with geometrically defined cutting edges designed to generate and/or finish toothed profiles through rolling engagement with the work piece.
In the skiving (also referred to as “power skiving”) of toothed work pieces with skiving wheels designed for this purpose, the dimensions of the skiving wheels as specified by their respective manufacturers enter directly or indirectly into the control settings for the skiving process.
Typically, the manufacturers will specify the outside diameter of the skiving wheel (measured at the tips of the teeth) as well as the height of the tool.
Other measurement methods which are used, e.g., for the contact measurement in the gear-shaping process, such as taking the measurements of the generating cutter, for example with a defined roller, based on which the dimensions of the tool are calculated, are only of limited use for skiving wheels, as the evaluation of such measurements is extremely complex and requires a multitude of input data.
In the just-mentioned gear-shaping process, the cutting edge of the generating cutter wheel as seen in the direction of its axis represents the geometry of a toothed profile of a spur gear in a transverse sectional plane, wherein said spur gear is meshing with the work piece in process like one gear with another (in the case of a straight-toothed cutter wheel). Or in the case of helical generating cutter wheels, at least the contour of the cutting edge as seen perpendicular to the surface normal and along the tooth trace represents the geometry of a toothed profile of a helical gear in a normal section, wherein said helical gear is meshing with the work piece in process like one helical gear with another. In contrast to these situations, the shape of the cutting edge of a skiving wheel will be different from the shape of the tooth gap to be cut in accordance with a specified tooth geometry. Given that in a skiving process, the respective axes of rotation of the work piece and of the tool will cross each other at an angle that is normally set between 10 and 30 degrees, a skiving wheel will for example no longer conform to an involute tooth shape as was the case with the generating cutter wheels mentioned above. As the power-skiving process can be expected to be known to practitioners in this field, further details will not be entered into at this point. A clear presentation of the process can be found in EP 2 537 615 A1.
Because of the reason that has just been explained, the information provided by manufacturers of skiving wheels will normally be limited to the diameter and the height. It has been found, however, that even with the knowledge of these dimensions of the skiving wheel there may be rejects in particular at the beginning of a production run of a series of tooth-profiled work pieces, as the latter can be out of tolerance in several different aspects, for example by being undersized in the base tangent length. In practice, the work pieces are brought to a measurement room where the measurements are taken. Based on the measurement results obtained thereby, corrections are made in the settings of the machine tool for the power-skiving process.
In view of the problems involved in the foregoing conventional procedure, the objective of the present invention is to simplify the practice of the power-skiving process in regard to the aforementioned aspects and to improve the power-skiving process, aiming in particular for high quality of the tooth-profiles produced, preferably already in the first piece of a manufacturing run.